<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <style>
        
        * {
            margin: 0;
            padding: 0;
        }
        body {
            background-color: #555555;
        }
        .yin-yang {
            width: 200px;
            height: 200px;
            border-radius: 50%;
            margin: 100px;
            background: linear-gradient(180deg, rgba(255,255,255,1) 0%, rgba(255,255,255,1) 50%, rgba(0,0,0,1) 50%, rgba(0,0,0,1) 100%);
            position: relative;
            margin: 100px;
            animation-name: spin;
            animation-duration: 3s;
            animation-iteration-count: infinite;
            animation-timing-function: linear;
        }
        .yin-yang::before {
            content: "";
            width: 100px;
            height: 100px;
            border-radius: 50%;
            position: absolute;
            top: 50px;
            left: 0;
            background: radial-gradient(circle, rgba(255,255,255,1) 0%, rgba(255,255,255,1) 24%, rgba(0,0,0,1) 24%);
        }
        .yin-yang::after {
            content: "";
            width: 100px;
            height: 100px;
            border-radius: 50%;
            position: absolute;
            top: 50px;
            right: 0;
            background: radial-gradient(circle, rgba(0,0,0,1) 0%, rgba(0,0,0,1) 24%, rgba(255,255,255,1) 24%);
        }
        @keyframes spin {
            form {
                transform: rotate(0deg);
            }
            to {
                transform: rotate(360deg);
            }
        }
    </style>
</head>
<body>
    <div class="yin-yang"></div>
</body>
</html>